The theme of the 56th Annual Thomas L. Petty Lung Conference is The Lung Microbiome: A New Frontier in Pulmonary Medicine. Emphasizing the integration of basic, translational and clinical sciences, the meeting will focus upon the lung microbiome and its interactions with the environment, genetics and diet in healthy states and disease. As an organ that is constantly exposed to the environment as well as the systemic circulation, the lung encounters inhaled particles that are certainly not sterile and an immune system that has to differentiate between self and non-self. Whether the lung has unique microbial populations that occupy specific niches is still a subject for debate. The 2013 Aspen Lung Conference will examine and discuss microbiota from well- studied mucosal surfaces (gut, skin) and the likely interplay with lung mucosa. Questions that remain to be answered and that will be addressed in this conference include: Is there crosstalk between the lung and the gut? Is there bacterial translocation from gut to lung? Is the lung microbiome established at birth? Does it reflect the mother's vaginal microbiome or is it a reflection of the microbiome in the upper airways? Are the interactions with the host primarily through the innate or adaptive immune systems? The overall objectives of this conference are: 1) To stimulate conversations and cross-pollination between pulmonary research scientists and physicians and basic scientists whose main focus is the identification and testing of microbiomes in various anatomical sites 2) To initiate a dialogue between microbiologists and researchers interested in pulmonary pathobiology. 3) To educate pulmonary scientists about the potential cross-talk between the microbiomes of the lung and various extrapulmonary sites 4) Provide an international forum for leading clinicians and researchers to exchange ideas relating to lung microbiome and its relationship to microbiomes at other anatomical sites 5) Fill a knowledge gap in the understanding of whether there is a unique lung microbiome 6) Stimulate new perspectives and further research in pulmonary microbiota in health and disease Determine if and how the alteration in the lung microbiome leads to or alters respiratory disorders 7) To create an environment that will lead to sustained interest among trainees